<template>
  <div>
    <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
      <div class="iconfont header-abs-back">&#xe605;</div>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      景点详情
      <router-link to="/">
        <div class="iconfont header-back">&#xe605;</div>
      </router-link>
    </div>
  </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop || document.body.scrollTop || window.pageYOffset
      console.log(top)
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  mounted () {
    window.addEventListener('scroll', this.handleScroll)
  },
  destroyed () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
  @import '~styles/varibles.styl'
  .header-abs
    position : absolute
    top : .2rem
    left : .2rem
    width : .8rem
    height : .8rem
    line-height : .8rem
    border-radius : .4rem
    text-align : center
    background : rgba(0, 0, 0, .8)
    .header-abs-back
      color : #FFFFFF
      font-size : .4rem
  .header-fixed
    z-index : 2
    position : fixed
    top : 0
    left : 0
    right : 0
    height : $headerHeight
    line-height : $headerHeight
    background : $bgColor
    text-align : center
    color : #FFFFFF
    font-size : .32rem
    .header-back
      position : absolute
      top : 0
      left : 0
      width : 0.64rem
      text-align : center
      color : #FFFFFF
      font-size : .4rem
</style>
